• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.365-377
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• 2022

Mammalian target of rapamycin (mTOR) is a serine-threonine kinase member of the cellular phosphatidylinositol 3-kinase (PI3K) pathway, which is involved in multiple biological functions by transcriptional and translational control. mTOR is a downstream mediator in the PI3K/Akt signaling pathway and plays a critical role in cell survival. In cancer, this pathway can be activated by membrane receptors, including the HER (or ErbB) family of growth factor receptors, the insulin-like growth factor receptor, and the estrogen receptor. In the present work, we congregated an electronic network of mTORC1 built on an assembly of data using natural language processing, consisting of 470 edges (activations/interactions and/or inhibitions) and 206 nodes representing genes/proteins, using the Cytoscape 3.6.0 editor and its plugins for analysis. The experimental design included the extraction of gene expression data related to five distinct types of cancers, namely, pancreatic ductal adenocarcinoma, hepatic cirrhosis, cervical cancer, glioblastoma, and anaplastic thyroid cancer from Gene Expression Omnibus (NCBI GEO) followed by pre-processing and normalization of the data using R & Bioconductor. ExprEssence plugin was used for network condensation to identify differentially expressed genes across the gene expression samples. Gene Ontology (GO) analysis was performed to find out the over-represented GO terms in the network. In addition, pathway enrichment and functional module analysis of the protein-protein interaction (PPI) network were also conducted. Our results indicated NOTCH1, NOTCH3, FLCN, SOD1, SOD2, NF1, and TLR4 as upregulated proteins in different cancer types highlighting their role in cancer progression. The MCODE analysis identified gene clusters for each cancer type with MYC, PCNA, PARP1, IDH1, FGF10, PTEN, and CCND1 as hub genes with high connectivity. MYC for cervical cancer, IDH1 for hepatic cirrhosis, MGMT for glioblastoma and CCND1 for anaplastic thyroid cancer were identified as genes with prognostic importance using survival analysis.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.448-458
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• 2020

We investigated the therapeutic effects of microRNA-139-5p in relation to osteoporosis of bone marrow-derived mesenchymal stem cell (BMSCs) and its underlying mechanisms. In this study we used a dexamethasone-induced in vivo model of osteoporosis and BMSCs were used for the in vitro model. Real-time quantitative polymerase chain reaction (RT-PCR) and gene chip were used to analyze the expression of microRNA-139-5p. In an osteoporosis rat model, the expression of microRNA-139-5p was increased, compared with normal group. Down-regulation of microRNA-139-5p promotes cell proliferation and osteogenic differentiation in BMSCs. Especially, up-regulation of microRNA-139-5p reduced cell proliferation and osteogenic differentiation in BMSCs. Overexpression of miR-139-5p induced Wnt/β-catenin and down-regulated NOTCH1 signaling in BMSCs. Down-regulation of miR-139-5p suppressed Wnt/β-catenin and induced NOTCH1 signaling in BMSCs. The inhibition of NOTCH1 reduced the effects of anti-miR-139-5p on cell proliferation and osteogenic differentiation in BMSCs. Activation of Wnt/β-catenin also inhibited the effects of anti-miR-139-5p on cell proliferation and osteogenic differentiation in BMSCs. Taken together, our results suggested that the inhibition of microRNA-139-5p promotes osteogenic differentiation of BMSCs via targeting Wnt/β-catenin signaling pathway by NOTCH1.

• Development and Reproduction
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• v.7 no.2
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• pp.69-80
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• 2003

The zebrafish(Danio rerio) is a pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. We show examples of positional cloning in two developmental mutants in zebrafish. headless: The severe head defects in headless(hdl) mutants are due to a mutation in T-cell factor-3(Tcf3). Loss of Tcf3 function in the hdl mutant reveals that Hdl represses Wnt target genes. The results provide genetic evidence that a component of the Wnt signaling pathway is essential in vertebrate head formation and patterning. mind bomb: Reduced lateral inhibition in mind bomb(mib) mutants permits too many neural precursors to differentiate as neurons. Positional cloning of mib revealed that it is a gene in the Notch pathway that encodes a ubiquitin E3 ligase. Mib interacts with the intracellular domain of Delta to promote its internalization. The results suggest a model for Notch activation where the Delta-Notch interaction is followed by endocytosis of Delta and transendocytosis of the Notch extracellular domain by the signaling cell.

• BMB Reports
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• v.42 no.5
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• pp.245-259
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• 2009

The process by which adult neural stem cells generate new and functionally integrated neurons in the adult mammalian brain has been intensely studied, but much more remains to be discovered. It is known that neural progenitors progress through distinct stages to become mature neurons, and this progression is tightly controlled by cell-cell interactions and signals in the neurogenic niche. However, less is known about the cell-intrinsic signaling required for proper progression through stages of adult neurogenesis. Techniques have recently been developed to manipulate genes specifically in adult neural stem cells and progenitors in vivo, such as the use of inducible transgenic mice and viral-mediated gene transduction. A critical mass of publications utilizing these techniques has been reached, making it timely to review which molecules are now known to play a cell-intrinsic role in regulating adult neurogenesis in vivo. By drawing attention to these isolated molecules (e.g. Notch), we hope to stimulate a broad effort to understand the complex and compelling cascades of intrinsic signaling molecules important to adult neurogenesis. Understanding this process opens the possibility of understanding brain functions subserved by neurogenesis, such as memory, and also of harnessing neural stem cells for repair of the diseased and injured brain.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.519-522
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• 2006

Purpose : Alagille syndrome is an autosomal dominant disorder with developmental abnormalities affecting the liver, heart, eyes, vertebrae, and craniofacial region. The Jagged1(JAG1) gene, which encodes a ligand of Notch, has been found mutated in Alagille syndrome. The aim of the study was to investigate the mutation analysis of JAG1 gene in Korean patients with Alagille syndrome. Methods : Genomic DNA was extracted from peripheral leukocytes of 6 patients. The 26 exons of JAG1 gene were amplified and PCR products were directly sequenced. Results : Two novel frameshift mutations were found. 118delC in exon 2 was found in a patient who developed hepatocellular carcinoma at 4 years of age. 999-1000delTG was identified in exon 7. Conclusion : Mutations identified in this study are expected to give rise to truncated proteins.

• Molecules and Cells
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• v.45 no.5
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• pp.329-342
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• 2022

The liver is the predominant metastatic site for pancreatic cancer. However, the factors that determine the liver metastasis and the specific molecular mechanisms are still unclear. In this study, we used human pancreatic cancer cell line Hs766T to establish Hs766T-L3, a subline of Hs766T with stable liver metastatic ability. We performed RNA sequencing of Hs766T-L3 and its parental cell line Hs766T, and revealed huge differences in gene expression patterns and pathway activation between these two cell lines. We correlated the difference in pathway activation with the expression of the four core transcriptional factors including STAT1, NR2F2, GATA2, and SMAD4. Using the TCGA database, we examined the relative expression of these transcription factors (TFs) in pan-cancer and their relationship with the prognosis of the pancreatic cancer. Among these TFs, we considered GATA2 is closely involved in tumor metastasis and may serve as a potential metastatic driver. Further in vitro and in vivo experiments confirmed that GATA2-mediated transcriptional activation of Notch3 promotes the liver metastasis of Hs766T-L3, and knockdown of either GATA2 or Notch3 reduces the metastatic ability of Hs766T-L3. Therefore, we claim that GATA2 may serve as a metastatic driver of pancreatic cancer and a potential therapeutic target to treat liver metastasis of pancreatic cancer.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.855-865
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• 2023

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small artery vasculopathy caused by mutations in the NOTCH3 gene on chromosome 19. Jeju Island has the highest reported prevalence of CADASIL patients in the world. Even though most studies on the neuroimaging characteristics of CADASIL have focused on Western populations, there are notable differences in Korean CADASIL patients compared to those in Western countries, which may impact their clinical manifestations and prognosis. Herein, this pictorial essay presents the neuroimaging patterns of CADASIL in patients in Korea, with an emphasis on the differences observed from previous reports based on a Western patient population.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.24-25
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• 2003

The zebrafish (Danio rerio) is now the pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. I will talk about positional cloning of two developmental mutants in zebrafish. The first mutant is headless: The vertebrate organizer can induce a complete body axis when transplanted to the ventral side of a host embryo by virtue of its distinct head and trunk inducing properties. Wingless/Wntantagonists secreted by the organizer have been identified as head inducers. Their ectopic expression can promote head formation, whereas ectopic activation of Wnt signalling during early gastrulation blocks head formation. These observations suggest that the ability of head inducers to inhibit Wntsignalling during formation of anterior structures is what distinguishes them from trunk inducers that permit the operation of posteriorizing Wnt signals. I describe the zebrafish headless (hdl) mutant and show that its severe head defects are due to a mutation in T-cell factor-3 (Tcf3), a member of the Tcf/Lef family. Loss of Tcf3 function in the hdl mutant reveals that hdl represses Wnt target genes. I provide genetic evidence that a component of the Wntsignalling pathway is essential in vertebrate head formation and patterning. Second mutant is mind bomb: Lateral inhibition, mediated by Notch signaling, leads to the selection of cells that are permitted to become neurons within domains defined by proneuralgene expression. Reduced lateral inhibition in zebrafish mib mutant embryos permits too many neural progenitors to differentiate as neurons. Positional cloning of mib revealed that it is a gene in the Notch pathway that encodes a RING ubiquitin ligase. Mib interacts with the intracellular domain of Delta to promote its ubiquitylation and internalization. Cell transplantation studies suggest that mib function is essential in the signaling cell for efficient activation of Notch in neighboring cells. (중략)

• Molecules and Cells
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• v.41 no.9
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• pp.842-852
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• 2018

Notch signaling is an evolutionarily conserved pathway and involves in the regulation of various cellular and developmental processes. Ligand binding releases the intracellular domain of Notch receptor (NICD), which interacts with DNA-bound CSL [CBF1/Su(H)/Lag-1] to activate transcription of target genes. In the absence of NICD binding, CSL down-regulates target gene expression through the recruitment of various corepressor proteins including SMRT/NCoR (silencing mediator of retinoid and thyroid receptors/nuclear receptor corepressor), SHARP (SMRT/HDAC1-associated repressor protein), and KyoT2. Structural and functional studies revealed the molecular basis of these interactions, in which NICD coactivator and corepressor proteins competitively bind to ${\beta}-trefoil$ domain (BTD) of CSL using a conserved ${\varphi}W{\varphi}P$ motif (${\varphi}$ denotes any hydrophobic residues). To date, there are conflicting ideas regarding the molecular mechanism of SMRT-mediated repression of CSL as to whether CSL-SMRT interaction is direct or indirect (via the bridge factor SHARP). To solve this issue, we mapped the CSL-binding region of SMRT and employed a 'one- plus two-hybrid system' to obtain CSL interaction-defective mutants for this region. We identified the CSL-interaction module of SMRT (CIMS; amino acid 1816-1846) as the molecular determinant of its direct interaction with CSL. Notably, CIMS contains a canonical ${\varphi}W{\varphi}P$ sequence (APIWRP, amino acids 1832-1837) and directly interacts with CSL-BTD in a mode similar to other BTD-binding corepressors. Finally, we showed that CSL-interaction motif, rather than SHARP-interaction motif, of SMRT is involved in transcriptional repression of NICD in a cell-based assay. These results strongly suggest that SMRT participates in CSL-mediated repression via direct binding to CSL.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3811-3816
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• 2015

Background: Hairy and enhancer of split 1 (Hes-1) protein is a downstream target of Notch signaling and is a basic helix-loop-helix transcriptional repressor. However, definitive evidence for a role in hepatocellular carcinoma (HCC) cells has not been reported. Here, Hes-1 was revealed to an important component of the Notch signaling cascade in HCC cell lines possessing different potential for lung metastasis. Materials and Methods: RNAi mediated by plasmid constructs was used to analyze the role of Hes-1 in MHCC-97L HCC cells by assessing proliferation, apoptosis, cell migration and matrigel invasion following transfection. Hes-1 protein expression analysis in HCC tissue was also conducted by immunohistochemistry. Results: Our studies revealed that Hes-1 was decreased in HCC cell lines with higher lung metastasis potential at both the mRNA and protein levels. Down-regulation of the Hes-1 gene in MHCC-97L cells resulted in increased cell proliferation, reduced apoptosis and increased migration and invasion. Conclusions: Hes-1 has potential prognostic value in post-surgical HCC patients and may be an independent prognostic indicator for overall survival and tumor recurrence. These findings have important implications for understanding the mechanisms by which Hes-1 participates in tumor proliferation and invasion.